1. Field of the Invention
The present invention generally relates to diverse data base management systems and more particularly relates to enhanced message handling techniques which provide sequencing of multiple messages between client and server applications.
2. Description of the Prior Art
Data base management systems are well known in the data processing art. Such commercial systems have been in general use for more than 20 years. One of the most successful data base management systems is available from Unisys Corporation and is called the Classic MAPPER® data base management system. The Classic MAPPER system can be reviewed using the Classic MAPPER User's Guide which may be obtained from Unisys Corporation.
The Classic MAPPER system, which runs on proprietary hardware also available from Unisys Corporation, provides a way for clients to partition data bases into structures called filing cabinets and drawers, as a way to offer a more tangible format. The MAPPER data base manager utilizes various predefined high-level instructions whereby the data base user may manipulate the data base to generate human-readable data presentations called “reports”. The user is permitted to prepare lists of the various predefined high-level instructions into data base manager programs called “MAPPER Script”. Thus, users of the Classic MAPPER system may create, modify, and add to a given data base and also generate periodic and aperiodic reports using various MAPPER Script.
However, with the Classic MAPPER system, as well as with similar proprietary data base management systems, the user must interface with the data base using a terminal coupled directly to the proprietary system and must access and manipulate the data using the MAPPER Script command language of Classic MAPPER. Ordinarily, that means that the user must either be co-located with the hardware which hosts the data base management system or must be coupled to that hardware through dedicated telephone, satellite, or other data links. Furthermore, the user usually needs to be schooled in the command language of Classic MAPPER (or other proprietary data base management system) to be capable of generating MAPPER Script.
This communication tends to be “interactive” over a session which involves a number of separate and individual transactions. That means that a sequence of messages is transferred between client and server applications. This communication requirement is completely inconsistent with the protocol of publically accessible digital data communication networks, such as the Internet, and is particularly problematic when implementing an interface between otherwise incompatible legacy data base management systems. As a result, prior approaches have tended to force users to individually transfer each of the sequential messages required for a given session.